RESUMO
Type I and III IFNs play diverse roles in bacterial infections, being protective for some but deleterious for others. Using RNA-sequencing transcriptomics we investigated lung gene expression responses to Bordetella pertussis infection in adult mice, revealing that type I and III IFN pathways may play an important role in promoting inflammatory responses. In B. pertussis-infected mice, lung type I/III IFN responses correlated with increased proinflammatory cytokine expression and with lung inflammatory pathology. In mutant mice with increased type I IFN receptor (IFNAR) signaling, B. pertussis infection exacerbated lung inflammatory pathology, whereas knockout mice with defects in type I IFN signaling had lower levels of lung inflammation than wild-type mice. Curiously, B. pertussis-infected IFNAR1 knockout mice had wild-type levels of lung inflammatory pathology. However, in response to infection these mice had increased levels of type III IFN expression, neutralization of which reduced lung inflammation. In support of this finding, B. pertussis-infected mice with a knockout mutation in the type III IFN receptor (IFNLR1) and double IFNAR1/IFNLR1 knockout mutant mice had reduced lung inflammatory pathology compared with that in wild-type mice, indicating that type III IFN exacerbates lung inflammation. In marked contrast, infant mice did not upregulate type I or III IFNs in response to B. pertussis infection and were protected from lethal infection by increased type I IFN signaling. These results indicate age-dependent effects of type I/III IFN signaling during B. pertussis infection and suggest that these pathways represent targets for therapeutic intervention in pertussis.
Assuntos
Infecções por Bordetella/imunologia , Bordetella pertussis/imunologia , Interferon Tipo I/imunologia , Interferons/imunologia , Infecções Respiratórias/imunologia , Fatores Etários , Animais , Infecções por Bordetella/genética , Bordetella pertussis/patogenicidade , Feminino , Interferon Tipo I/genética , Interferons/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Mutação , Receptores de Interferon/deficiência , Receptores de Interferon/genética , Receptores de Interferon/imunologia , Infecções Respiratórias/genética , Análise de Sequência de RNA , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Transcriptoma , Interferon lambdaRESUMO
Whooping cough (pertussis) is a severe pulmonary infectious disease caused by the bacteria Bordetella pertussis. Pertussis infects an estimated 24 million people annually, resulting in >150,000 deaths. The NIH placed pertussis on the list of emerging pathogens in 2015. Antibiotics are ineffective unless administered before the onset of the disease characteristic cough. Therefore, there is an urgent need for novel pertussis therapeutics. We have shown that sphingosine-1-phosphate receptor (S1PR) agonists reduce pertussis inflammation without increasing bacterial burden. Transcriptomic studies were performed to identify this mechanism and allow for the development of pertussis therapeutics that specifically target problematic inflammation without sacrificing bacterial control. These data suggested a role for triggering receptor expressed on myeloid cells-1 (TREM-1). TREM-1 cell surface receptor functions as an amplifier of inflammatory responses. Expression of TREM-1 is increased in response to bacterial infection of mucosal surfaces. In mice, B. pertussis infection results in Toll-like receptor 9 (TLR9)-dependent increased expression of TREM-1 and its associated cytokines. Interestingly, S1PR agonists dampen pulmonary inflammation and TREM-1 expression. Mice challenged intranasally with B. pertussis and treated with ligand-dependent (LP17) and ligand-independent (GF9) TREM-1 inhibitors showed no differences in bacterial burden and significantly reduced tumor necrosis factor-α (TNF-α) and C-C motif chemokine ligand 2 (CCL-2) expression compared to controls. Mice receiving TREM-1 inhibitors showed reduced pulmonary inflammation compared to controls, indicating that TREM-1 promotes inflammatory pathology, but not bacterial control, during pertussis infection. This implicates TREM-1 as a potential therapeutic target for the treatment of pertussis.
Assuntos
Bordetella pertussis/imunologia , Inflamação/imunologia , Inflamação/metabolismo , Receptor Gatilho 1 Expresso em Células Mieloides/metabolismo , Animais , Modelos Animais de Doenças , Inflamação/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Mieloides/metabolismo , Células Mieloides/microbiologia , Fator de Necrose Tumoral alfa/metabolismo , Coqueluche/imunologia , Coqueluche/metabolismo , Coqueluche/microbiologiaRESUMO
Incidence of whooping cough (pertussis), a bacterial infection of the respiratory tract caused by the bacterium Bordetella pertussis, has reached levels not seen since the 1950s. Antibiotics fail to improve the course of disease unless administered early in infection. Therefore, there is an urgent need for the development of antipertussis therapeutics. Sphingosine-1-phosphate receptor (S1PR) agonists have been shown to reduce pulmonary inflammation during Bordetella pertussis infection in mouse models. However, the mechanisms by which S1PR agonists attenuate pertussis disease are unknown. We report the results of a transcriptome sequencing study examining pulmonary transcriptional responses in B. pertussis-infected mice treated with S1PR agonist AAL-R or vehicle control. This study identified peptidoglycan recognition protein 4 (PGLYRP4) as one of the most highly upregulated genes in the lungs of infected mice following S1PR agonism. PGLYRP4, a secreted, innate mediator of host defenses, was found to limit early inflammatory pathology in knockout mouse studies. Further, S1PR agonist AAL-R failed to attenuate pertussis disease in PGLYRP4 knockout (KO) mice. B. pertussis virulence factor tracheal cytotoxin (TCT), a secreted peptidoglycan breakdown product, induces host tissue damage. TCT-oversecreting strains were found to drive an early inflammatory response similar to that observed in PGLYRP4 KO mice. Further, TCT-oversecreting strains induced significantly greater pathology in PGLYRP4-deficient animals than their wild-type counterparts. Together, these data indicate that S1PR agonist-mediated protection against pertussis disease is PGLYRP4 dependent. Our data suggest PGLYRP4 functions, in part, by preventing TCT-induced airway damage.
Assuntos
Bordetella pertussis/imunologia , Proteínas de Transporte/metabolismo , Receptores de Lisoesfingolipídeo/agonistas , Coqueluche/imunologia , Animais , Modelos Animais de Doenças , Regulação Bacteriana da Expressão Gênica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Bordetella pertussis produces several toxins that affect host-pathogen interactions. Of these, the major toxins that contribute to pertussis infection and disease are pertussis toxin, adenylate cyclase toxin-hemolysin and tracheal cytotoxin. Pertussis toxin is a multi-subunit protein toxin that inhibits host G protein-coupled receptor signaling, causing a wide array of effects on the host. Adenylate cyclase toxin-hemolysin is a single polypeptide, containing an adenylate cyclase enzymatic domain coupled to a hemolysin domain, that primarily targets phagocytic cells to inhibit their antibacterial activities. Tracheal cytotoxin is a fragment of peptidoglycan released by B. pertussis that elicits damaging inflammatory responses in host cells. This chapter describes these three virulence factors of B. pertussis, summarizing background information and focusing on the role of each toxin in infection and disease pathogenesis, as well as their role in pertussis vaccination.
Assuntos
Toxina Adenilato Ciclase/toxicidade , Bordetella pertussis/patogenicidade , Toxina Pertussis/toxicidade , Fatores de Virulência de Bordetella/toxicidade , Adenilil Ciclases/fisiologia , Toxinas Bacterianas , Bordetella pertussis/enzimologia , Bordetella pertussis/genética , Proteínas Hemolisinas/fisiologia , Humanos , Fatores de Virulência , Coqueluche/microbiologia , Coqueluche/prevenção & controleRESUMO
Recent data have demonstrated the potential of sphingosine 1-phosphate (S1P) receptor (S1PR) agonism in the treatment of infectious diseases. A previous study used a murine model of Bordetella pertussis infection to demonstrate that treatment with the S1PR agonist AAL-R reduces pulmonary inflammation during infection. In the current study, we showed that this effect is mediated via the S1PR1 on LysM+ (myeloid) cells. Signaling via this receptor results in reduced lung inflammation and cellular recruitment as well as reduced morbidity and mortality in a neonatal mouse model of disease. Despite the fact that S1PRs are pertussis toxin-sensitive G protein-coupled receptors, the effects of AAL-R were pertussis toxin insensitive in our model. Furthermore, our data demonstrate that S1PR agonist administration may be effective at therapeutic time points. These results indicate a role for S1P signaling in B. pertussis-mediated pathology and highlight the possibility of host-targeted therapy for pertussis.
Assuntos
Anti-Inflamatórios/administração & dosagem , Inflamação/tratamento farmacológico , Toxina Pertussis/antagonistas & inibidores , Receptores de Lisoesfingolipídeo/agonistas , Esfingosina/administração & dosagem , Coqueluche/tratamento farmacológico , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Inflamação/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Mieloides/metabolismo , Toxina Pertussis/metabolismo , Esfingosina/análogos & derivados , Receptores de Esfingosina-1-Fosfato , Coqueluche/patologiaRESUMO
In infants, Bordetella pertussis can cause severe disease, manifested as pronounced leukocytosis, pulmonary hypertension, and even death. The exact cause of death remains unknown, and no effective therapies for treating fulminant pertussis exist. In this study, a neonatal mouse model of critical pertussis is characterized, and a central role for pertussis toxin (PT) is described. PT promoted colonization, leukocytosis, T cell phenotypic changes, systemic pathology, and death in neonatal but not adult mice. Surprisingly, PT inhibited lung inflammatory pathology in neonates, a result which contrasts dramatically with observed PT-promoted pathology in adult mice. Infection with a PT-deficient strain induced severe pulmonary inflammation but not mortality in neonatal mice, suggesting that death in these mice was not associated with impaired lung function. Dissemination of infection beyond the lungs was also detected in neonatal mice, which may contribute to the observed systemic effects of PT. We propose that it is the systemic activity of pertussis toxin and not pulmonary pathology that promotes mortality in critical pertussis. In addition, we observed transmission of infection between neonatal mice, the first report of B. pertussis transmission in mice. This model will be a valuable tool to investigate causes of pertussis pathogenesis and identify potential therapies for critical pertussis.
Assuntos
Bordetella pertussis/patogenicidade , Interações Hospedeiro-Patógeno , Leucocitose/microbiologia , Pulmão/microbiologia , Toxina Pertussis/toxicidade , Coqueluche/microbiologia , Fatores Etários , Animais , Animais Recém-Nascidos , Bordetella pertussis/crescimento & desenvolvimento , Bordetella pertussis/imunologia , Modelos Animais de Doenças , Humanos , Lactente , Leucocitose/imunologia , Leucocitose/mortalidade , Leucocitose/patologia , Pulmão/imunologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/imunologia , Neutrófilos/microbiologia , Neutrófilos/patologia , Toxina Pertussis/biossíntese , Toxina Pertussis/imunologia , Análise de Sobrevida , Linfócitos T/imunologia , Linfócitos T/microbiologia , Linfócitos T/patologia , Coqueluche/imunologia , Coqueluche/mortalidade , Coqueluche/patologiaRESUMO
Recent pertussis resurgence represents a major public health concern. Currently, there are no effective treatments for critical pertussis in infants. Recent data have demonstrated the potential of sphingosine-1-phosphate receptor (S1PR) agonism in the treatment of infectious diseases. We used the murine Bordetella pertussis model to test the hypothesis that treatment with S1PR agonist AAL-R reduces pulmonary inflammation during infection. AAL-R treatment resulted in reduced expression of inflammatory cytokines and chemokines and attenuated lung pathology in infected mice. These results demonstrate a role for sphingosine-1-phosphate (S1P) signaling in B. pertussis-mediated pathology and highlight the possibility of host-targeted therapy for pertussis.
Assuntos
Bordetella pertussis/imunologia , Pulmão/patologia , Pneumonia Bacteriana/patologia , Receptores de Lisoesfingolipídeo/agonistas , Animais , Modelos Animais de Doenças , Pulmão/microbiologia , Camundongos Endogâmicos C57BL , Pneumonia Bacteriana/microbiologiaRESUMO
Pertussis disease, characterized by severe and prolonged coughing episodes, can progress to a critical stage with pulmonary inflammation and death in young infants. However, there are currently no effective treatments for pertussis. We previously studied the role of pertussis toxin (PT), an important Bordetella pertussis virulence factor, in lung transcriptional responses to B. pertussis infection in mouse models. One of the genes most highly upregulated in a PT-dependent manner encodes an epithelial transporter of bicarbonate, chloride, and thiocyanate, named pendrin, that contributes to asthma pathology. In this study, we found that pendrin expression is upregulated at both gene and protein levels in the lungs of B. pertussis-infected mice. Pendrin upregulation is associated with PT production by the bacteria and with interleukin-17A (IL-17A) production by the host. B. pertussis-infected pendrin knockout (KO) mice had higher lung bacterial loads than infected pendrin-expressing mice but had significantly reduced levels of lung inflammatory pathology. However, reduced pathology did not correlate with reduced inflammatory cytokine expression. Infected pendrin KO mice had higher levels of inflammatory cytokines and chemokines than infected pendrin-expressing mice, suggesting that these inflammatory mediators are less active in the airways in the absence of pendrin. In addition, treatment of B. pertussis-infected mice with the carbonic anhydrase inhibitor acetazolamide reduced lung inflammatory pathology without affecting pendrin synthesis or bacterial loads. Together these data suggest that PT contributes to pertussis pathology through the upregulation of pendrin, which promotes conditions favoring inflammatory pathology. Therefore, pendrin may represent a novel therapeutic target for treatment of pertussis disease.
Assuntos
Proteínas de Transporte de Ânions/metabolismo , Bordetella pertussis/crescimento & desenvolvimento , Interações Hospedeiro-Patógeno , Toxina Pertussis/metabolismo , Coqueluche/patologia , Coqueluche/fisiopatologia , Animais , Proteínas de Transporte de Ânions/genética , Carga Bacteriana , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Lactente , Interleucina-17/metabolismo , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pneumonia Bacteriana/patologia , Pneumonia Bacteriana/fisiopatologia , Transportadores de SulfatoRESUMO
BACKGROUND: The need to develop new, improved treatments for tuberculosis (TB) remains urgent, and the repurposing of existing drugs represents a possible shortcut to market. Recently, there has been significant interest in host-directed adjuvant therapy to enhance bacillary killing. HMG-CoA reductase inhibitors (statins), which are among the most commonly prescribed drugs, have immunomodulatory properties and improve the clinical outcomes of bacterial infections. METHODS: We studied the tuberculocidal activity of simvastatin alone and in combination with first-line anti-TB drugs in J774 macrophages and during chronic TB infection. RESULTS: Exposure to 5 µM simvastatin significantly increased the tuberculocidal activity of isoniazid in J774 macrophages at Day 3 after infection versus isoniazid alone (P=0.02). Similarly, relative to the standard oral regimen of rifampicin (10 mg/kg), isoniazid (10 mg/kg) and pyrazinamide (150 mg/kg) given five times weekly, the addition of 25 mg/kg simvastatin enhanced bacillary killing, reducing the number of lung cfu by an additional 1 log10 at Day 28 (P<0.01) and by a further 1.25 log10 at Day 56 (P<0.01). CONCLUSIONS: The potential additive activity of simvastatin to first-line TB treatment holds promise. However, further studies to identify the optimal statin and dosing are required. In addition the ability of combination treatment with statins to accelerate the time required to achieve a stable cure remains to be explored.
Assuntos
Antituberculosos/uso terapêutico , Sinergismo Farmacológico , Sinvastatina/uso terapêutico , Tuberculose/tratamento farmacológico , Animais , Antituberculosos/farmacologia , Carga Bacteriana , Linhagem Celular , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Quimioterapia Combinada/métodos , Feminino , Isoniazida/farmacologia , Isoniazida/uso terapêutico , Pulmão/microbiologia , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Camundongos Endogâmicos BALB C , Pirazinamida/farmacologia , Pirazinamida/uso terapêutico , Rifampina/farmacologia , Rifampina/uso terapêutico , Sinvastatina/farmacologia , Resultado do TratamentoRESUMO
Uncovering the complexity of systems in non-model organisms is critical for understanding arthropod immunology. Prior efforts have mostly focused on Dipteran insects, which only account for a subset of existing arthropod species in nature. Here we use and develop advanced techniques to describe immune cells (hemocytes) from the clinically relevant tick Ixodes scapularis at a single-cell resolution. We observe molecular alterations in hemocytes upon feeding and infection with either the Lyme disease spirochete Borrelia burgdorferi or the rickettsial agent Anaplasma phagocytophilum. We reveal hemocyte clusters exhibiting defined signatures related to immunity, metabolism, and proliferation. Depletion of phagocytic hemocytes affects hemocytin and astakine levels, two I. scapularis hemocyte markers, impacting blood-feeding, molting behavior, and bacterial acquisition. Mechanistically, astakine alters hemocyte proliferation, whereas hemocytin affects the c-Jun N-terminal kinase (JNK) signaling pathway in I. scapularis. Altogether, we discover a role for tick hemocytes in immunophysiology and provide a valuable resource for comparative biology in arthropods.
Assuntos
Anaplasma phagocytophilum , Artrópodes , Borrelia burgdorferi , Ixodes , Doença de Lyme , Animais , Hemócitos , Ixodes/microbiologia , Borrelia burgdorferi/fisiologiaRESUMO
BACKGROUND: Preclinical evaluation of tuberculosis drugs is generally limited to mice. However, necrosis and hypoxia, key features of human tuberculosis lesions, are lacking in conventional mouse strains. METHODS: We used C3HeB/FeJ mice, which develop necrotic lesions in response to Mycobacterium tuberculosis infection. Positron emission tomography in live infected animals, postmortem pimonidazole immunohistochemistry, and bacterial gene expression analyses were used to assess whether tuberculosis lesions in C3HeB/FeJ are hypoxic. Efficacy of combination drug treatment, including PA-824, active against M. tuberculosis under hypoxic conditions, was also evaluated. RESULTS: Tuberculosis lesions in C3HeB/FeJ (but not BALB/c) were found to be hypoxic and associated with up-regulation of known hypoxia-associated bacterial genes (P < .001). Contrary to sustained activity reported elsewhere in BALB/c mice, moxifloxacin and pyrazinamide (MZ) combination was not bactericidal beyond 3 weeks in C3HeB/FeJ. Although PA-824 added significant activity, the novel combination of PA-824 and MZ was less effective than the standard first-line regimen in C3HeB/FeJ. CONCLUSIONS: We demonstrate that tuberculosis lesions in C3HeB/FeJ are hypoxic. Activities of some key tuberculosis drug regimens in development are represented differently in C3HeB/FeJ versus BALB/c mice. Because C3HeB/FeJ display key features of human tuberculosis, this strain warrants evaluation as a more pathologically relevant model for preclinical studies.
Assuntos
Granuloma/complicações , Granuloma/patologia , Hipóxia/patologia , Mycobacterium tuberculosis/patogenicidade , Tuberculose/patologia , Animais , Antituberculosos/administração & dosagem , Compostos Aza/administração & dosagem , Modelos Animais de Doenças , Fluoroquinolonas , Perfilação da Expressão Gênica , Genes Bacterianos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C3H , Moxifloxacina , Nitroimidazóis/administração & dosagem , Tomografia por Emissão de Pósitrons , Pirazinamida/administração & dosagem , Quinolinas/administração & dosagem , Resultado do Tratamento , Tuberculose/tratamento farmacológicoRESUMO
Pertussis, caused by Bordetella pertussis, is a resurgent respiratory disease but the molecular mechanisms underlying pathogenesis are poorly understood. We recently showed the importance of type I and type III interferon (IFN) induction and signaling for the development of lung inflammation in B. pertussis-infected mouse models. Classically, these IFNs are induced by signaling through a variety of pattern recognition receptors (PRRs) on host cells. Here, we found that the PRR signaling adaptor molecules MyD88 and TRIF contribute to IFN induction and lung inflammatory pathology during B. pertussis infection. However, the PRRs Toll-like receptors (TLR) 3 and TLR4, which signal through TRIF and MyD88, respectively, played no role in IFN induction. Instead, the DNA-sensing PRRs, TLR9 and STING, were important for induction of type I/III IFN and promotion of inflammatory pathology, indicating that DNA is a major inducer of lung IFN responses in B. pertussis infection. These results increase our understanding of this host-pathogen interaction and identify potential targets for host-directed therapies to reduce B. pertussis-mediated pathology.
Assuntos
Interferon Tipo I , Pneumonia , Coqueluche , Camundongos , Animais , Bordetella pertussis , Fator 88 de Diferenciação Mieloide/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Interferon lambda , DNA , Proteínas Adaptadoras de Transporte VesicularRESUMO
Uncovering the complexity of systems in non-model organisms is critical for understanding arthropod immunology. Prior efforts have mostly focused on Dipteran insects, which only account for a subset of existing arthropod species in nature. Here, we describe immune cells or hemocytes from the clinically relevant tick Ixodes scapularis using bulk and single cell RNA sequencing combined with depletion via clodronate liposomes, RNA interference, Clustered Regularly Interspaced Short Palindromic Repeats activation (CRISPRa) and RNA-fluorescence in situ hybridization (FISH). We observe molecular alterations in hemocytes upon tick infestation of mammals and infection with either the Lyme disease spirochete Borrelia burgdorferi or the rickettsial agent Anaplasma phagocytophilum. We predict distinct hemocyte lineages and reveal clusters exhibiting defined signatures for immunity, metabolism, and proliferation during hematophagy. Furthermore, we perform a mechanistic characterization of two I. scapularis hemocyte markers: hemocytin and astakine. Depletion of phagocytic hemocytes affects hemocytin and astakine levels, which impacts blood feeding and molting behavior of ticks. Hemocytin specifically affects the c-Jun N-terminal kinase (JNK) signaling pathway, whereas astakine alters hemocyte proliferation in I. scapularis. Altogether, we uncover the heterogeneity and pleiotropic roles of hemocytes in ticks and provide a valuable resource for comparative biology in arthropods.
RESUMO
Whooping cough is caused by Bordetella pertussis that releases pertussis toxin (PT) which comprises enzyme A-subunit PTS1 and binding/transport B-subunit. After receptor-mediated endocytosis, PT reaches the endoplasmic reticulum from where unfolded PTS1 is transported to the cytosol. PTS1 ADP-ribosylates G-protein α-subunits resulting in increased cAMP signaling. Here, a role of target cell chaperones Hsp90, Hsp70, cyclophilins and FK506-binding proteins for cytosolic PTS1-uptake is demonstrated. PTS1 specifically and directly interacts with chaperones in vitro and in cells. Specific pharmacological chaperone inhibition protects CHO-K1, human primary airway basal cells and a fully differentiated airway epithelium from PT-intoxication by reducing intracellular PTS1-amounts without affecting cell binding or enzyme activity. PT is internalized by human airway epithelium secretory but not ciliated cells and leads to increase of apical surface liquid. Cyclophilin-inhibitors reduced leukocytosis in infant mouse model of pertussis, indicating their promising potential for developing novel therapeutic strategies against whooping cough.
Assuntos
Bordetella pertussis/enzimologia , Sistemas de Liberação de Medicamentos , Inibidores Enzimáticos/farmacologia , Células Epiteliais/metabolismo , Leucocitose , Chaperonas Moleculares , Toxina Pertussis/toxicidade , Animais , Bordetella pertussis/metabolismo , Bordetella pertussis/patogenicidade , Células CHO , Cricetulus , Células Epiteliais/microbiologia , Células HEK293 , Humanos , Leucocitose/induzido quimicamente , Leucocitose/tratamento farmacológico , Leucocitose/metabolismo , Camundongos , Chaperonas Moleculares/antagonistas & inibidores , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismoRESUMO
Pertussis, caused by respiratory tract infection with the bacterial pathogen Bordetella pertussis, has long been considered to be a toxin-mediated disease. Bacteria adhere and multiply extracellularly in the airways and release several toxins, which have a variety of effects on the host, both local and systemic. Predominant among these toxins is pertussis toxin (PT), a multi-subunit protein toxin that inhibits signaling through a subset of G protein-coupled receptors in mammalian cells. PT activity has been linked with severe and lethal pertussis disease in young infants and a detoxified version of PT is a common component of all licensed acellular pertussis vaccines. The role of PT in typical pertussis disease in other individuals is less clear, but significant evidence supporting its contribution to pathogenesis has been accumulated from animal model studies. In this review we discuss the evidence indicating a role for PT in pertussis disease, focusing on its contribution to severe pertussis in infants, modulation of immune and inflammatory responses to infection, and the characteristic paroxysmal cough of pertussis.
Assuntos
Toxina Pertussis/toxicidade , Coqueluche/etiologia , Animais , Humanos , Coqueluche/imunologiaRESUMO
Mycobacterium tuberculosis is the etiologic agent of tuberculosis. The demand for new chemotherapeutics with unique mechanisms of action to treat (multi)resistant strains is an urgent need. The objective of this work was to test the effect of manganese(II) and copper(II) phenanthroline/dicarboxylate complexes against M. tuberculosis. The water-soluble Mn(II) complexes, [Mn2(oda)(phen)4(H2O)2][Mn2(oda)(phen)4(oda)2]·4H2O (1) and {[Mn(3,6,9-tdda)(phen)2]·3H2O·EtOH}n (3) (odaH2 = octanedioic acid, phen = 1,10-phenanthroline, tddaH2 = 3,6,9-trioxaundecanedioic acid), and water-insoluble complexes, [Mn(ph)(phen)(H2O)2] (5), [Mn(ph)(phen)2(H2O)]·4H2O (6), [Mn2(isoph)2(phen)3]·4H2O (7), {[Mn(phen)2(H2O)2]}2(isoph)2(phen)·12H2O (8) and [Mn(tereph)(phen)2]·5H2O (9) (phH2 = phthalic acid, isophH2 = isophthalic acid, terephH2 = terephthalic acid), robustly inhibited the viability of M. tuberculosis strains, H37Rv and CDC1551. The water-soluble Cu(II) analog of (1), [Cu2(oda)(phen)4](ClO4)2·2.76H2O·EtOH (2), was significantly less effective against both strains. Whilst (3) retarded H37Rv growth much better than its soluble Cu(II) equivalent, {[Cu(3,6,9-tdda)(phen)2]·3H2O·EtOH}n (4), both were equally efficient against CDC1551. VERO and A549 mammalian cells were highly tolerant to the Mn(II) complexes, culminating in high selectivity index (SI) values. Significantly, in vivo studies using Galleria mellonella larvae indicated that the metal complexes were minimally toxic to the larvae. The Mn(II) complexes presented low MICs and high SI values (up to 1347), indicating their auspicious potential as novel antitubercular lead agents.
RESUMO
Co-infection with Mycobacterium tuberculosis accelerates progression from HIV to AIDS. Our previous studies showed that M. tuberculosis complex, unlike M. smegmatis, enhances TLR2-dependent susceptibility of CD4+ T cells to HIV. The M. tuberculosis complex produces multiple TLR2-stimulating lipoproteins, which are absent in M. smegmatis. M. tuberculosis production of mature lipoproteins and TLR2 stimulation is dependent on cleavage by lipoprotein signal peptidase A (LspA). In order to determine the role of potential TLR2-stimulating lipoproteins on mycobacterial-mediated HIV infectivity of CD4+ T cells, we generated M. smegmatis recombinant strains overexpressing genes encoding various M. bovis BCG lipoproteins, as well as a Mycobacterium bovis BCG strain deficient in LspA (ΔlspA). Exposure of human peripheral blood mononuclear cells (PBMC) to M. smegmatis strains overexpressing the BCG lipoproteins, LprF (p<0.01), LprH (p<0.05), LprI (p<0.05), LprP (p<0.001), LprQ (p<0.005), MPT83 (p<0.005), or PhoS1 (p<0.05), resulted in increased HIV infectivity of CD4+ T cells isolated from these PBMC. Conversely, infection of PBMC with ΔlspA reduced HIV infectivity of CD4+ T cells by 40% relative to BCG-infected cells (p<0.05). These results may have important implications for TB vaccination programs in areas with high mother-to-child HIV transmission.
Assuntos
Ácido Aspártico Endopeptidases/metabolismo , Proteínas de Bactérias/metabolismo , Linfócitos T CD4-Positivos/virologia , HIV-1/fisiologia , Lipoproteínas/metabolismo , Mycobacterium bovis/metabolismo , Mycobacterium smegmatis/metabolismo , Mycobacterium tuberculosis/fisiologia , Receptor 2 Toll-Like/metabolismo , Adulto , Linfócitos T CD4-Positivos/metabolismo , Células Cultivadas , Suscetibilidade a Doenças , Técnicas de Introdução de Genes , Genes Bacterianos , Interações Hospedeiro-Patógeno , Humanos , Mycobacterium bovis/genética , Mycobacterium smegmatis/genética , Sinais Direcionadores de Proteínas , Proteínas Recombinantes de Fusão/metabolismo , VirulênciaRESUMO
Whooping cough, or pertussis, incidence has reached levels not seen since the 1950s. Previous studies have shown that antibiotics fail to improve the course of disease unless diagnosed early. Early diagnosis is complicated by the non-diagnostic presentation of disease early in infection. This review focuses on previous attempts at developing novel host-directed therapies for the treatment of pertussis. In addition, two novel approaches from our group are discussed. Manipulation of the signaling pathway of sphingosine-1-phosphate, a lipid involved in many immune processes, has shown great promise, but is in its infancy. Pendrin, a host epithelial anion exchanger upregulated in the airways with B. pertussis infection, appears to drive mucus production and dysregulation of airway surface liquid pH and salinity. In addition to detailing these potential new therapeutic targets, the need for greater focus on the neonatal model of disease is highlighted.
Assuntos
Tratamento Farmacológico/métodos , Imunoterapia/métodos , Coqueluche/tratamento farmacológico , Animais , Descoberta de Drogas/tendências , Inibidores Enzimáticos/metabolismo , Humanos , Fatores Imunológicos/metabolismo , Lisofosfolipídeos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Transportadores de Sulfato , Coqueluche/epidemiologiaRESUMO
Tuberculosis (TB) which is caused by the resilient pathogen Mycobacterium tuberculosis (MTB) has re-emerged to become a leading public health problem in the world. The growing number of multi-drug resistant MTB strains and the more recently emerging problem with the extensively drug resistant strains of the pathogen are greatly undermining conventional anti-TB therapeutic strategies which are lengthy and expose patients to toxicity and other unwanted side effects. The search for new anti-TB drugs essentially involves either the repurposing of existing organic drugs which are now off patent and already FDA approved, the synthesis of modified analogues of existing organic drugs, with the aim of shortening and improving drug treatment for the disease, or the search for novel structures that offer the possibility of new mechanisms of action against the mycobacterium. Inorganic medicinal chemistry offers an alternative to organic drugs through opportunities for the design of therapeutics that target different biochemical pathways. The incorporation of metal ions into the molecular structure of a potential drug offers the medicinal chemist an opportunity to exploit structural diversity, have access to various oxidation states of the metal and also offer the possibility of enhancing the activity of an established organic drug through its coordination to the metal centre. In this review, we summarize what is currently known about the antitubercular capability of metal complexes, their mechanisms of action and speculate on their potential applications in the clinic.
Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose/tratamento farmacológico , Antituberculosos/química , Química Farmacêutica , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Estrutura Molecular , Mycobacterium tuberculosis/isolamento & purificaçãoRESUMO
BACKGROUND: We have previously identified Mycobacterium tuberculosis PknD to be an important virulence factor required for the pathogenesis of central nervous system (CNS) tuberculosis (TB). Specifically, PknD mediates bacillary invasion of the blood-brain barrier, which can be neutralized by specific antisera, suggesting its potential role as a therapeutic target against TB meningitis. METHODOLOGY/PRINCIPAL FINDINGS: We utilized an aerosol challenge guinea pig model of CNS TB and compared the protective efficacy of recombinant M. tuberculosis PknD subunit protein with that of M. bovis BCG against bacillary dissemination to the brain. BCG vaccination limited the pulmonary bacillary burden after aerosol challenge with virulent M. tuberculosis in guinea pigs and also reduced bacillary dissemination to the brain (Pâ=â0.01). PknD vaccination also offered significant protection against bacterial dissemination to the brain, which was no different from BCG (P>0.24), even though PknD vaccinated animals had almost 100-fold higher pulmonary bacterial burdens. Higher levels of PknD-specific IgG were noted in animals immunized with PknD, but not in BCG-vaccinated or control animals. Furthermore, pre-incubation of M. tuberculosis with sera from PknD-vaccinated animals, but not with sera from BCG-vaccinated or control animals, significantly reduced bacterial invasion in a human blood-brain barrier model (P<0.01). CONCLUSION: Current recommendations for administering BCG at birth are based on protection gained against severe disease, such as TB meningitis, during infancy. We demonstrate that vaccination with recombinant M. tuberculosis PknD subunit offers a novel strategy to protect against TB meningitis, which is equivalent to BCG in a guinea pig model. Moreover, since BCG lacks the PknD sensor, BCG could also be boosted to develop a more effective vaccine against TB meningitis, a devastating disease that disproportionately affects young children.